1. Field of the Invention
The present invention relates to magnetic head positioning means for a magnetic disk drive, and more particularly, to magnetic head positioning means for a sector servo system magnetic disk drive wherein servo information is recorded on a magnetic disk before being incorporated into a magnetic disk drive.
2. Description of the Related Art
Conventionally, servo information is stored onto a magnetic disk after the magnetic disk has been installed in a magnetic disk drive. Accordingly, there has been a requirement for magnetic disk drives to have a function for performing high-precision servo information recording, in order to meet demands for narrowing of servo tracks. As a result, it is necessary to provide a high-precision positioning mechanism and hence the magnetic disk drive becomes expensive.
On the other hand, one technique for improving positioning characteristics in order to achieve narrowing of servo tracks is a system as disclosed in Japanese Patent Laid-open No.(Hei)9-282820 which compensates for the repeatable runout components in the servo signal which are generated when servo information is written to a magnetic disk. In this conventional compensating system, the repeatable runout components are measured and compensated for.
However, in order to counteract repeatable runout components caused by the excitation of the spindle motor which rotates the magnetic disk, or by deformation of the magnetic disk, these components being particularly notable when servo information is recorded onto the magnetic disk by means of this system before installing the disk in a magnetic disk drive, a large memory space is required because of the need to store compensation values for a large number of tracks.